The invention relates to a method for producing a piston oil control ring.
Producing non-coated piston oil control rings with tapered running rails is generally known. The problem until now was that coatings for these tapered running surfaces could not be provided with a uniform lapping along the complete ring circumference and on both running rails with the same radial dimensions or defined only in the upper region to ensure that a reduction in the oil consumption is a given during the running-in behavior.
Reference DE-A 42 36 641 discloses a piston oil control ring for internal combustion engines, which operates jointly with a coil wire spring that pushes its two running rails against the corresponding cylinder wall. The running rails in this case have a tapered design and are coated with a wear-resistant chrome layer. However, one disadvantage to be mentioned here is that when arranging two running rails and coating these with a wear-resistant coating, different running surfaces with respect to height and radial expansion are unavoidably formed in the region of the running rails during the subsequent lapping operation. As a result, the running behavior of the piston oil control ring will vary during the operating state. In addition to differences in the wear behavior of the two running rails or the associated running surfaces, this also results in a non-optimum oil consumption, particularly during the running-in behavior of the piston oil control ring.